Principles of Naval Architecture for students

Although there are still practitioners of the traditional art of manual fairing of ship lines, the geometry of most hull forms ranging from small yachts to the largest commercial and naval ships are now almost invariably developed using one of the commercially available hull modeling software packages. Such software normally includes, in addition to the hull modeling and display functions, routines for the computation of hydrostatics, stability and other hull properties. It may form a part of a comprehensive computer-based design and manufacturing system or it may be included in a shipboard computer-based operational system used for cargo load monitoring and damage control. The present volume presents first, the theoretical basis for these hull modeling systems and second, the procedures for computing hull geometric, buoyancy and other properties by mathematical methods utilizing such models. The emphasis is upon the nomenclature and fundamentals underlying several different methods of hull geometrical modeling with the intention of providing the understanding needed to use intelligently both existing and future tools. Some topics included in the volume are continuity and fairness of surfaces, B-spline and NURBS representation, ruled and developable surfaces, subdivision surfaces, and classic computational topics such as hydrostatic properties and initial stability. This is a subject area characterized by a continuing stream of innovation and new software products so the objective here is to present the basis needed to understand and keep abreast of new developments in the field.

1. Principles of Naval Architecture

2. Identification of 1.Principle bulkheads Bulkheads are inner walls within the hull of a ship, used to separate it into smaller compartments.

3. 2. Keel plate the keel is the primary structural member and backbone of the vessel which runs along the centerline of the bottom plate around which the hull of the ship is built.

4. 3. Decks Main Deck - The main deck is the first continuous watertight deck that runs from the bow to the stern Forecastle Deck – Poop Deck - A poop deck is a short, high deck of a ship, located in the aft (back) of a ship. It was traditionally used to provide a high point for observations and navigation. Most modern ships don’t have a poop deck, as it is no longer needed . Upper Deck - The deck that covers the hull of the vessel from its fore to its aft is the upper deck. It is the topmost deck on a ship. In all vessels, the upper deck is the biggest deck amongst all other decks .

5. 5.Fore peak tank- The forepeak is the space between the stem and the collision bulkhead. The distance between the stem and the collision bulkhead must be at least 5 per cent of the ships’s length and not more than 8 per cent. The forepeak tank is the part of the forepeak up to the deck. 6.The after peak tank -occupies the space between the stern and the afterpeak tank bulkhead. Both peak tanks may be used for fresh water or ballast .

6. 7.Double bottom: An inner bottom (or tank top) may be provided at a minimum height above the bottom shell, and maintained watertight to the  bilges . This provides a considerable margin of safety, since in the event of bottom shell damage only the double bottom space may be flooded. The space is not wasted but utilized to carry oil fuel and fresh water required for the ship, as well as providing ballast capacity

7. Coefficient Form